Great Lakes Shipping Breaking Out of the Off-season
Posted on: April 1, 2019
Ice cover just over 20% on the Great Lakes on March 25, 2019. Canadian and U.S. Coast Guard icebreaking vessels will be clearing things up as the Great Lakes shipping industry gears up for spring and summer. (Credit: NASA Earth Observatory image by Joshua Stevens, using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview)

The Off-season Ends When Locks Reopen

After a highly successful shipping season in 2018, ports are optimistic that 2019 will provide equally substantial traffic. Shipping within the great lakes continues throughout the winter, but to a much lesser degree because the Great Lakes’ Soo locks and the St. Lawrence Seaway’s Montreal – Lake Ontario locks are shut down for maintenance and repair.

Icebreaking ships, USCGC Mackinaw and USCGC Alder, transit through the Soo Locks. Photo from the USACE Detroit District Facebook Page (Credit: U.S. Army Corps of Engineers Detroit District)

The off-season ends when these locks are reopened and ice breakers head out to the northern ports to get things moving again; this year the CCGS Samuel Risley, USCGC Mackinaw and USCGC Alder headed north through the Soo Locks on March 20th. On March 25th, the Stewart J. Cort was the first of the shipping season’s big ships to pass through the Soo locks. The Montreal – Lake Ontario locks opened on Tuesday March 26th.

Ice Breakers

Ice cover on Lake Superior reached 90% in early March, but the ice quickly began to dissipate and is now down to about 25% according to NOAA data. But that is still more ice than the coast guard has seen in several years. Ice breakers from the Canadian and U.S. coast guards work together to create passable shipping lanes in the Great Lakes. If you are curious about where the icebreaking ships are currently located on the lake, you can look for them using the live map on (they fall under the “Tugs & Special Craft” category and are light blue).

Canadian icebreakers

The Canadian Coast Guard (CCG) has an ice fleet of 15 that is dedicated to ice breaking efforts along Canadian shores on the East and West coasts, in the Arctic and in the Great Lakes. The fleet boasts 2 heavy icebreakers, 4 medium icebreakers, 9 multipurpose vessels and 2 hovercrafts. Vessels are assigned to one of three regions: the Atlantic, the Central and Arctic, or the Western Region.

The CCGS Samuel Risley, one of the Canadian Coast Guard’s light icebreakers that operate in the Great Lakes, is named after Samuel Risley, a pioneer in shipping safety regulation in the late 1850s. (Credit: U.S. Army Corps of Engineers Detroit District – On her way, Public Domain)

According to the CCG website, two Central and Arctic region light icebreakers—the medium-endurance CCGS Samuel Risley and the high-endurance CCGS Griffon multi-tasked vessels—are assigned to the Great Lakes throughout the winter, but additional vessels are used at the beginning and end of the ice breaking season.

The CCGS Griffon is the Canadian Coast Guard’s high endurance multi-tasked vessel light icebreaker. It is named after Le Griffon, one of the first sailing ships constructed to travel across the Great Lakes. (Credit: simon*** from England – CCGS Griffon on the Welland Canal, Canada, CC BY 2.0)

Canadian icebreakers active in the Great Lakes and St. Lawrence Seaway on March 30, 2019 at 12:00pm EDT:

  • CCGS Samuel Risley – Port of Thunder Bay
  • CCGS Pierre Radisson – Lake Erie
  • CCGS Griffon – northeast Lake Ontario near the St. Lawrence River
  • CCGS Des Groseillers – St. Lawrence River
  • CCGS Captain Molly Kool – Gulf of St. Lawrence

U.S. icebreakers

The USCGC Alder, also known as the “King of the Waters,” operates throughout the Great Lakes but mainly works in Lake Superior and northern Lake Michigan. (Credit: Pete Markham. Some Rights Reserved, CC BY-SA 2.0)

The U.S. Coast Guard Atlantic Area’s Ninth District units are dedicated to all coast guard operations in the Great Lakes, Saint Lawrence Seaway and parts of the surrounding states. Vessels involved in icebreaking operations fall under the Cutters Unit, and include the USCGC Alder, Biscayne Bay, Bristol Bay, Hollyhock, Katmai Bay, Mackinaw, Mobile Bay, Morrow Bay, and Neah Bay. In Lake Superior you will mostly hear about the USCGC Alder and USCGC Mackinaw.

The USCGC Mackinaw is the U.S. Coast Guard’s only heavy icebreaker in the Great Lakes. (Credit: U.S. Coast Guard)

U.S. icebreakers active in the Great Lakes and St. Lawrence Seaway on March 30, 2019 at 12:00pm EDT:

  • USCGC Alder – Port of Thunder Bay
  • USCGC Mackinaw – Passing Whitefish Point destined for Whitefish Bay
  • USCGC Katmai Bay – Munuscong Lake
  • USCGC Bristol Bay and Neah Bay – Northern Lake Michigan


USACE Press Release: “The Soo Locks open as 2019 shipping season begins”

Great Lakes St. Lawrence Seaway System: Canadian and U.S. Press Releases

CBC: “Canadian Coast Guards ‘looking for new recruits’ in video showing ice breaking process in Thunder Bay, Ont”

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